Influence of temperature and exploitation time on hardness and micro-structure of a welded joint in a reactor mantle

Abstract This paper presents the analysis of the influence of temperature and exploitation time on the cross-sectional hardness and micro-structure changes of characteristic zones of a welded joint made of low-alloyed Cr-Mo steel A-387 Gr. B. Exploited parent metal is a part of a reactor mantle which was working for over 40 years and is in the damage repair stage, i.e. part of its mantle is being replaced with new material. Cross-sectional hardness of a butt-welded joint was measured and macroscopic investigation of the welded joint and microstructural analysis of the parent material, weld metal and the heat affected zone were performed. The comparison of parameters obtained for characteristic zones of a welded joint provides a way to meausre the justifiability of the selected welding technology.